stress Flashcards
(28 cards)
which neuroendocrine protection systems does stress activate?
sympatho-adrenergic system (SAS)
- short term stress response
- adrenal medulla releasing catecholaines (adrenaline and noradrenaline)
hypothalamic-pituitary-adrenal axis (HPA)
- long term stress response
- adrenal cortex to release hormones
what is stress?
a situation that upsets an animal’s homeostatic balance = stressor
what is predominantly used to regulate the stress response?
feedback loops
what are the 3 stages of the stress response?
and who came up with it and name?
- alarm reaction
- resistance stage
- recovery (when stressor dealt with)/ exhaustion stage (when stressor not dealt with)
Selye - general adaptation syndrome
what happens during the alarm reaction in the stress response?
- stressor perceived by pituitary-adrenal system
- SAS system prepares body for action by activating coping mechanisms
e. g increase in blood pressure, tachycardia (rapid HR) and tachypnoea (rapid breathing) - HPA system releases energy stores
what happens during the resistance stage in the stress response?
- body attemots to re-establish physiological balance (homeostasis)
- if stressor persists then stress hormones and arousal levels remain high (combat stress)
what happens during the exhaustion stage in the stress response?
- when stress is not dealt with and continues for long enough
- depletes resources and exhausts body’s defenses
- stress-related illnesses develop
what stimulates the alarm response?
sudden, unexpected appearance of stressor
non-specific immediate behavioural response - startled
what does the SAS activate during the alarm reaction?
and what does one of the things release?
brainstem
vagal nerve
adrenal medulla
- releases noradrenaline
- releases adrenaline
what is the effect of adrenaline in the alarm reaction?
- raises HR, increases blood flow to muscles and non-essential organs
- stimulates glycogenolysis (glycogen to glucose for energy)
- adipose tissue to release fat (break down tirglycerides)
- widens bronchioles
what is the effect of noradrenalne in the alarm reaction?
- stimulates alpha receptors in muscle, contraction of receptors redirects blood to essential organs and increases blood pressure
what does the HPA axis do in the alarm reaction?
ACTH stimulates adrenal cortex to release cortisol which leads to…
slower-acting passive coping mechanisms (fight or flight not been effective)
adaptive redirection of energy:
- gluconeogenesis (creation of glucose)
- lipolysis (breaking down of fat)
- inhibits growth
- oxygen and nutrients to brain
what leads to chronic stress?
sustained activation of HPA axis due to severe long-lasting aversive events
what are the depeltion of resources during the exhaustion stage?
sugars mobilised and energy not stored (muscle wasting)
hypertension (damage to blood vessels due to high BP)
digestion, growth and immunity suppressed
give examples of systemic stressors?
and what are they?
visceral nociceptors (internal organs pain)
somatic nociceptors (skin and muscle pain)
inflammatory signals
stimulation of baroreceptors (pressure) or osmoreceptors (imbalance of water pressure)
- actual threats
give examples of neurogenic stressors?
and what are they?
anticipation of predators
dangers associated with novel enviro
- anticipated threats
what are the main stressors in some animals?
interactions with conspecifics
e.g dominance
what do most naturally occuring stressors involve?
combination of both systemic (actual) and neurogenic stressors (anticipated)
what is eustress?
as opposed to distress
perturbation can be dealt with effectively
stress response quickly terminated once homeostasis restored
what is distress?
as opposed to eustress
chronic hypo/hyperactivation of HPA axis
may be harmful and lead to abnormal behaviour
what decides between whether eustressor distress?
both quality and intensity of stressor
characteristics of individual challenged by stresso e.g genetics and history and emotional state
what is Lazarus’s transactional theory regarding coping with stress?
dynamic relationship between:
- enviro demands (stressor)
- individual’s psychological resources for dealing (coping ability)
stress response occurs from perceived imbalance between these demands and resources
what are the 2 forms of cognitive appraisal?
and what do they take into account?
- primary
- secondary
- take both personal and enviro factors into account
what is primary appraisal?
significance of stressor in terms of goals and values
initial decision of whether threat perceived e.g is it irrelevant
